Incidence and prevalence rates of diabetes mellitus in Italy from routine data: a methodological assessment

Human Leukocyte Antigen (HLA) and Islet Autoantibodies Are Tools to Characterize Type 1 Diabetes in Arab Countries: Emphasis on Kuwait

The incidence rate of type 1 diabetes in Kuwait had been increasing exponentially and has doubled in children ≤ 14 years old within almost two decades. Therefore, there is a dire need for a careful systematic familial cohort study. Several immunogenetic factors affect the pathogenesis of the disease. The human leukocyte antigen (HLA) accounts for the major genetic susceptibility to the disease. The triggering agents initiate disease onset by type 1 destruction of pancreatic β-cells. Both HLA and anti-islet antibodies can be used to characterize, predict susceptibility to the disease, innovate, or delay the β-cell destruction. Evidence from prospective longitudinal studies suggested that the underlying disease process represents a continuum that begins before the symptoms are clinically evident. Autoimmunity of the functional pancreatic β-cells results in symptomatic type 1 diabetes and lifelong insulin dependence. The autoantibodies against glutamic acid decarboxylase (GADA), insulinoma antigen-2 (IA-2A), insulin (IAA), and zinc transporter-8 (ZnT-8A) comprise the most reliable biomarkers for type 1 diabetes in both children and adults. Although Kuwait is the second among the top 10 countries with a high incidence rate of type 1 diabetes, there have been no proper diagnostic and prediction tools as per the World Health Organization. The Kuwaiti Type 1 Diabetes Study (KADS) was initiated to understand the disease pathogenesis as well as the HLA and anti-islet autoantibody profile of type 1 diabetes in Kuwait. Understanding the disease sequela in a homogenous gene pool and highly consanguineous population of Kuwaitis could help solve the challenges and pathogenesis, as well as hasten the prevention, of type 1 diabetes.

Increasing incidence of type 1 diabetes between 1986 and 2015 in Bauru, Brazil

AIMS

To assess temporal trends in the incidence of type 1 diabetes in Bauru, São Paulo State, Brazil from 1986 to 2015.

RESEARCH DESIGN AND METHODS

The yearly incidence of type 1 diabetes (per 100,000/yr) from 1986 to 2015 was determined in children ≤14yr of age, using individual case notification and the capture and recapture method.

RESULTS

During thirty years (1986-2015), 302 cases were diagnosed in our population. The overall incidence was of 12.8/100,000 (95% CI: 11.2-14.4), ranging from 2.8/100,000 in 1987 to 25.6/100,000 in 2013 with a 9.1-fold variation. It was non-significantly higher in girls [13.7 (95% CI: 11.4-16.1)] than in boys [12.0 (95% CI: 9.8-14.2)] (p=0.48) and significantly higher in the 5-9yr [14.6 (95% CI: 11.8-17.4)] and 10-14yr [15.8 (95% CI: 12.7-18.8)] age ranges compared to the 0-4yr [8.1 (95% CI: 6.0-10.2)] age range (p<0.001). The majority of diagnoses were made in colder months. The patterns of incidence were very high and high in 80.0% of the study-years.

CONCLUSIONS

The incidence of type1 diabetes in children ≤14yr has increased in Bauru, Brazil, in the last thirty years, in approximately 3.1% annually, with an absolute crude increase of 2.5-fold. These findings pose Brazil as a country with high incidence of type 1 diabetes. All Brazilian regions should be enrolled in future studies to determine the factors that contribute to the predisposition to type 1 diabetes in our population and to the steep rise in its incidence.

The role of geographical ecological studies in identifying diseases linked to UVB exposure and/or vitamin D

Using a variety of approaches, researchers have studied the health effects of solar ultraviolet (UV) radiation exposure and vitamin D. This review compares the contributions from geographical ecological studies with those of observational studies and clinical trials. Health outcomes discussed were based on the author's knowledge and include anaphylaxis/food allergy, atopic dermatitis and eczema, attention deficit hyperactivity disorder, autism, back pain, cancer, dental caries, diabetes mellitus type 1, hypertension, inflammatory bowel disease, lupus, mononucleosis, multiple sclerosis, Parkinson disease, pneumonia, rheumatoid arthritis, and sepsis. Important interactions have taken place between study types; sometimes ecological studies were the first to report an inverse correlation between solar UVB doses and health outcomes such as for cancer, leading to both observational studies and clinical trials. In other cases, ecological studies added to the knowledge base. Many ecological studies include other important risk-modifying factors, thereby minimizing the chance of reporting the wrong link. Laboratory studies of mechanisms generally support the role of vitamin D in the outcomes discussed. Indications exist that for some outcomes, UVB effects may be independent of vitamin D. This paper discusses the concept of the ecological fallacy, noting that it applies to all epidemiological studies.

Global epidemiology of type 1 diabetes in young adults and adults: a systematic review

Background

Although type 1 diabetes (T1D) can affect patients of all ages, most epidemiological studies of T1D focus on disease forms with clinical diagnosis during childhood and adolescence. Clinically, adult T1D is difficult to discriminate from certain forms of Type 2 Diabetes (T2D) and from Latent Autoimmune Diabetes in Adults (LADA).

We searched the information available worldwide on the incidence of T1D among individuals over 15 years of age, and which diagnostic criteria should be used use to qualify T1D in adults. We then studied the variation of T1D incidence with age in adults, and compared it to the incidence in the <15 years-old.

Methods

A systematic review of the literature was performed to retrieve original papers in English, French and Spanish published up to November 6, 2014, reporting the incidence of T1D among individuals aged over 15 years. The study was carried out according to the PRISMA recommendations.

Results

We retrieved information reporting incidence of T1D among individuals aged more than 15 years in 35 countries, and published in 70 articles between 1982 and 2014. Specific anti-beta-cell proteins or C-peptide detection were performed in 14 of 70 articles (20%). The most frequent diagnostic criteria used were clinical symptoms and immediate insulin therapy. Country-to-country variations of incidence in those aged >15 years paralleled those of children in all age groups. T1D incidence was larger in males than in females in 44 of the 54 (81%) studies reporting incidence by sex in people >15 years of age. The overall mean male-to-female ratio in the review was 1.47 (95% CI = 1.33-1.60, SD = 0.49, n = 54, p = <0.0001). Overall, T1D incidence decreased in adulthood, after the age of 14 years.

Conclusions

Few studies on epidemiology of T1D in adults are available worldwide, as compared to those reporting on children with T1D. The geographical variations of T1D incidence in adults parallel those reported in children. As opposed to what is known in children, the incidence is generally larger in males than in females. There is an unmet need to evaluate the incidence of autoimmune T1D in adults, using specific autoantibody detection, and to better analyze epidemiological specificities – if any – of adult T1D.

PROSPERO registration number

CRD42012002369.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1591-y) contains supplementary material, which is available to authorized users.

Covariation of the incidence of type 1 diabetes with country characteristics available in public databases

BACKGROUND

The incidence of Type 1 Diabetes (T1D) in children varies dramatically between countries. Part of the explanation must be sought in environmental factors. Increasingly, public databases provide information on country-to-country environmental differences.

METHODS

Information on the incidence of T1D and country characteristics were searched for in the 194 World Health Organization (WHO) member countries. T1D incidence was extracted from a systematic literature review of all papers published between 1975 and 2014, including the 2013 update from the International Diabetes Federation. The information on country characteristics was searched in public databases. We considered all indicators with a plausible relation with T1D and those previously reported as correlated with T1D, and for which there was less than 5% missing values. This yielded 77 indicators. Four domains were explored: Climate and environment, Demography, Economy, and Health Conditions. Bonferroni correction to correct false discovery rate (FDR) was used in bivariate analyses. Stepwise multiple regressions, served to identify independent predictors of the geographical variation of T1D.

FINDINGS

T1D incidence was estimated for 80 WHO countries. Forty-one significant correlations between T1D and the selected indicators were found. Stepwise Multiple Linear Regressions performed in the four explored domains indicated that the percentages of variance explained by the indicators were respectively 35% for Climate and environment, 33% for Demography, 45% for Economy, and 46% for Health conditions, and 51% in the Final model, where all variables selected by domain were considered. Significant environmental predictors of the country-to-country variation of T1D incidence included UV radiation, number of mobile cellular subscriptions in the country, health expenditure per capita, hepatitis B immunization and mean body mass index (BMI).

CONCLUSIONS

The increasing availability of public databases providing information in all global environmental domains should allow new analyses to identify further geographical, behavioral, social and economic factors, or indicators that point to latent causal factors of T1D.

An easy, fast, effective tool to monitor the incidence of type 1 diabetes among children aged 0-4 years in Italy: the Italian Hospital Discharge Registry (IHDR)

National data of type 1 diabetes incidence are currently missing in Italy. To fill this gap, we estimated the national rate of first hospitalizations for type 1 diabetes among children aged 0-4 years and resident in Italy, as well as rates for each of the twenty-one Italian regions. We extracted the first episode of hospitalization in years 2005-2010 from the Italian Hospital Discharge Registry (IHDR). Record-linkage procedure and cleansing data method were applied to exclude prevalent cases and potentially miscoded patients. At the end, 2,250 incident hospitalizations for type 1 diabetes were extracted. In the years 2005-2010, the mean nation-wide first hospitalization rate for type 1 diabetes in children aged 0-4 years was 13.4 (95% CI 12.8-14.0), 14.1 (95% CI 13.3-14.9) in males and 12.7 (95% CI 11.9-13.4) in females. A geographically heterogeneous pattern of incidence was found: even excluding Sardinia, incidence for this age range and calendar period tended to be slightly higher in Southern than in Northern Italy. Our incidence of first hospitalizations corresponds to the estimates of disease incidence obtained with different data sources by other authors in selected Italian regions. We provide, for the first time ever, the estimate of type 1 diabetes incidence for the overall population aged 0-4 years resident in Italy. When methodological cautions are adopted, IHDR emerges as a reasonable proxy of type 1 diabetes incidence and as a cost-effective tool for public health purposes.

Association of HCV with diabetes mellitus: an Egyptian case-control study

Background

The highest Hepatitis C Virus (HCV) prevalence in the world occurs in Egypt. Several studies from different parts of the world have found that 13% to 33% of patients with chronic HCV have associated diabetes, mostly type II Diabetes Mellitus (DM). In Egypt the prevalence of DM is 25.4% among HCV patients. Therefore, it is important to identify the magnitude of the problem of diabetes in order to optimize the treatment of chronic hepatitis C.

Methods

The objective of this case-control study was to evaluate the prevalence of DM and other extrahepatic (EH) manifestations among patients with different HCV morbidity stages including asymptomatic, chronic hepatic and cirrhotic patients. In this study, 289 HCV patients older than 18 were selected as cases. Also, 289 healthy controls were included. Laboratory investigations including Liver Function tests (LFT) and blood glucose level were done. Also serological assays including cryoglobulin profile, rheumatoid factor, antinuclear antibody, HCV-PCR were performed.

Results

Out of 289 HCV cases, 40 (13.84%) were diabetic. Out of 289 healthy controls, 12 (4.15%) were diabetic. It was found that the diabetic HCV group mean age was [48.1 (± 9.2)]. Males and urbanians represented 72.5% and 85% respectively. Lower level of education was manifested in 52.5% and 87.5% were married. In the nondiabetic HCV group mean age was [40.7 (± 10.4)]. Males and urbanians represented 71.5% and 655% respectively. secondary and higher level of education was attained in 55.4% and 76.7% were married. Comparing between the diabetic HCV group and the non diabetic HCV group, age, residence and alcohol drinking were the only significant factors affecting the incidence of diabetes between the two groups. There was no significant difference regarding sonar findings although cirrhosis was more prevalent among diabetic HCV cases and the fibrosis score was higher in diabetic HCV patients than among the non diabetic HCV cases.

Conclusion

The diabetic patients in the HCV group were older, more likely to have a history of alcohol drinking than the non diabetic HCV cases. Age and alcohol drinking are factors that could potentially contribute to the development of type 2 diabetes. Logistic regression analyses showed that age and residence in urban regions were the predictive variables that could be associated with the presence of diabetes. Alcohol consumption was not a significant predictive factor.

Onset of type 1 diabetes mellitus during peginterferon alpha-2b plus ribavirin treatment for chronic hepatitis C

A 61-year-old man was observed to develop type 1 diabetes mellitus following a 3-month treatment with recombinant alpha-2b peginterferon combined with ribavirin for chronic hepatitis C. Serum samples, collected before the start of therapy and 2 months after the diagnosis of diabetes mellitus, revealed islet-cell antibodies at a titer of 20 and 40 JDF-U, respectively, and glutamic acid decarboxylase autoantibodies at a value of 76.5 and 196 IU/ml, respectively. Antibodies to second islet autoantigen were persistently negative. HLA class II typing revealed the presence of DRB1*04/DRB1*14, DQA1*0303-0104 and DQB1*04-0503 alleles. Eight months after the onset of type 1 diabetes mellitus, the patient is still receiving 30 IU insulin daily; the liver function tests are normal and serum hepatitis C virus RNA is negative. These data confirm that, in patients with potential diabetes mellitus, the disease may become manifest as a side-effect during therapy with peginterferon-alpha plus ribavirin. The patient as a candidate for interferon treatment should therefore be investigated, in addition to thyroid autoimmunity, also for pancreatic autoantibodies before starting therapy.

No evidence of diabetes-specific CD38 (ADP ribosil cyclase/cyclic ADP-ribose hydrolase) autoantibodies by liquid-phase immunoprecipitation

AIMS/HYPOTHESIS

Autoantibodies to the ADP ribosyl cyclase/cyclic ADP-ribose hydrolase CD38 have been suggested to be markers of autoimmunity in Type 1 and Type 2 diabetes. The aim of this study was to develop a fluid phase assay for population screening.

METHODS

Human recombinant CD38 was cloned and expressed by in vitro transcription and translation for fluid phase radio-binding assay, as a fusion protein in COS7 cells for fluid phase immunoprecipitation, and as a fusion protein for western blot assays. Antibody binding to each recombinant protein was measured in sera from patients with Type 1 diabetes, Type 2 diabetes and control subjects.

RESULTS

Immunoprecipitation of radio-labelled in vitro transcribed and translated CD38 was low in all sera, including monoclonal anti-CD38 antibodies, with no difference between patients and control subjects. Monoclonal antibodies to CD38, but not patient or control sera immunoprecipitated recombinant CD38 fusion protein expressed in COS7 cells. Antibody binding to recombinant CD38 in solid-phase western blot assay was detected in sera from 2% of patients with Type 1 diabetes, 6% of patients with Type 2 diabetes, and 8% of control subjects.

CONCLUSIONS

This study failed to detect diabetes relevant binding of antibodies to recombinant CD38 using liquid-phase methods. Formal comparison of anti-CD38 antibody detection between laboratories is suggested.

A moderately low phosphate intake may provide health benefits analogous to those conferred by UV light - a further advantage of vegan diets

Although exposure to ultraviolet light is often viewed as pathogenic owing to its role in the genesis of skin cancer and skin aging, there is growing epidemiological evidence that such exposure may decrease risk for a number of more serious cancers, may have a favorable impact on blood pressure and vascular health, and may help to prevent certain autoimmune disorders - in addition to its well-known influence on bone density. Most likely, these health benefits are reflective of improved vitamin D status. Increased synthesis or intake of vitamin D can be expected to down-regulate parathyroid hormone (PTH), and to increase autocrine synthesis of its active metabolite calcitriol in certain tissues; these effects, in turn, may impact cancer risk, vascular health, immune regulation, and bone density through a variety of mechanisms. Presumably, a truly adequate supplemental intake of vitamin D - manyfold higher than the grossly inadequate current RDA - could replicate the benefits of optimal UV exposure, without however damaging the skin. Diets moderately low in bioavailable phosphate - like many vegan diets - might be expected to have a complementary impact on disease risks, inasmuch as serum phosphate suppresses renal calcitriol synthesis while up-regulating that of PTH. A proviso is that the impact of dietary phosphorus on bone health is more equivocal than that of vitamin D. Increased intakes of calcium, on the other hand, down-regulate the production of both PTH and calcitriol - the latter effect may explain why the impact of dietary calcium on cancer risk (excepting colon cancer), hypertension, and autoimmunity is not clearly positive. An overview suggests that a vegan diet supplemented with high-dose vitamin D should increase both systemic and autocrine calcitriol production while suppressing PTH secretion, and thus should represent a highly effective way to achieve the wide-ranging health protection conferred by optimal UV exposure.

Type 1 diabetes mellitus in patients with chronic hepatitis C before and after interferon therapy

Type 1 diabetes mellitus is the result of an autoimmune process characterized by pancreatic beta cell destruction. It has been reported that chronic hepatitis C infection is associated with type 2 diabetes mellitus, but not with type 1. Although the prevalence of markers of pancreatic autoimmunity in hepatitis C virus-positive patients is not significantly different to that reported in the general population, it increases during alpha-interferon therapy from 3 to 7%, probably due to the immunostimulatory effects of this cytokine. To date, 31 case reports of type 1 diabetes mellitus related to interferon treatment have been published. Type 1 diabetes mellitus occurs more frequently in patients treated for chronic hepatitis C than for other conditions and is irreversible in most cases. In 50% of these patients, markers of pancreatic autoimmunity predated treatment, the majority of cases having a genetic predisposition. Thus, in predisposed individuals, alpha-interferon can either induce or accelerate a diabetogenic process already underway. We suggest that islet cell autoantibodies and glutamic acid decarboxylase autoantibodies should be investigated before and during interferon treatment in order to identify subjects at high risk of developing type 1 diabetes mellitus.

Incidence of insulin-dependent diabetes (IDDM) and non-insulin-dependent diabetes (NIDDM) (0-34 years at onset) in Benghazi, Libya

The incidence of insulin-dependent diabetes (IDDM) and non-insulin-dependent diabetes (NIDDM) in Benghazi, Libya in the < 35-year age group during the period 1981-1990 are reported. Incidence data for IDDM were based on prospective registration of patients while incidence data for NIDDM were based on analysis of files. Case ascertainment of IDDM cases was estimated to be > 95%. Incidence of total diabetes (IDDM and NIDDM) (per 100000 population) was significantly higher in females (43.8; 95% confidence Interval (CI) 40.6-47.2) than in males (28.9, 26.6-31.3) (P < 0.001). The overall incidence rates of IDDM and NIDDM were 9.0 (CI, 8.1-10.0) and 27.3 (CI, 25.4-28.2), respectively. Rates of IDDM were 9.4 (CI, 8.1-10.9) among males and 8.5 (CI, 7.3-10.0) among females. Rates of NIDDM were 19.6 (CI, 18.1-22.2) among males and 35.3 (CI, 32.4-37.8) among females. IDDM patients showed a female predominance in the 0- to 14-year age range (P > 0.05) and a male predominance in the 15- to 34-year age range (P > 0.05). NIDDM showed equal incidence in males and females in the 0- to 14-year age range and twofold higher incidence in females than in males in the 15- to 34-year age group (P < 0.001). Yearly variation and seasonality of onset were not significant in IDDM cases (P > 0.05). Fifty-six percent of NIDDM cases were obese compared to only 6% of IDDM cases. The study revealed that diabetes mellitus is a common chronic disease in children and young Libyan Arabs. It has shown that NIDDM in Benghazi is twofold higher in females than in males in the 15- to 34-year age group. It has also shown that age per se is not a reliable criterion for the classification of diabetes into IDDM and NIDDM.

Diabetes mellitus in schizophrenic patients

Studies conducted in the United States and Japan indicate that diabetes mellitus is more common among schizophrenic patients than among the general population. The prevalence of known diabetes was examined in 95 schizophrenic patients aged 45 to 74 years admitted to a long-term care facility in Italy. The overall prevalence of diabetes was 15.8% (95% confidence interval, 12.1% to 19.5%), and increased from 0% in those younger than 50 years, through 12.9% in the 50- to 59-year age group, and to 18.9% in the 60- to 69-year age group, and then decreased to 16.7% in those aged 70 to 74 years. These rates are considerably higher than those reported from population surveys in Italy, and indicate that a higher prevalence of diabetes in schizophrenic patients may be a universal phenomenon. The clinical picture indicated that in all cases this was the common variant of type II (non-insulin-dependent) diabetes mellitus. Diabetes was more common in patients not receiving neuroleptics than in those who were receiving such treatment. There was no association between diabetes and the use of anticholinergic drugs.

A survey of adverse events in 11,241 patients with chronic viral hepatitis treated with alfa interferon

AIMS

The aim of this study was to assess the incidence of fatal, life-threatening side effects and the de novo appearance of non-hepatic morbidity during interferon alfa therapy for chronic viral hepatitis. The relationship of these adverse events to actual total dose and duration of interferon was also evaluated.

METHODS

We conducted a retrospective study at 73 Italian centers of 11,241 consecutive patients with chronic viral hepatitis who underwent interferon alfa treatment.

RESULTS

Five patients died during interferon therapy due to liver failure (n = 4) or complications arising from sepsis. Life-threatening side effects were observed in eight patients: two cases where depression developed and led to a suicide attempt and six patients with bone marrow suppression (granulocytes < 500/mm3 or platelets < 25,000/mm3). These symptoms and signs completely disappeared after interferon withdrawal. During interferon treatment, 131 patients developed the following de novo non-hepatic disorders: symptomatic thyroid disease (n = 71), impotence (n = 5), systemic autoimmune disease (n = 5), immune-mediated dermatologic disease (n = 14), diabetes mellitus (n = 10), cardiovascular disease (n = 7), psychosis n = 10), seizures (n = 4), peripheral neuropathy (n = 3) and hemolytic anemia (n = 2). Most of these complications are reversible or can be ameliorated. Fatal or life-threatening side effects were not related to actual total dose or duration of interferon alfa, while the majority of patients with de novo non-hepatic morbidity received medium/high doses (> 200 million units) of interferon alfa or were treated for periods longer than 16 weeks (68% and 80%, respectively).

CONCLUSIONS

Treatment with interferon alfa may have fatal or life-threatening side effects, their incidence in this study being low (0.04% and 0.07%, respectively) and perhaps no different than in untreated patients with chronic viral hepatitis. Moreover de novo non-hepatic morbidity occurred in 1.2% of patients, and the dose and duration of interferon therapy seem important in determining the frequency of this complication. The development of clinically-overt thyroid disease was most common.

Epidemiology of known diabetes in Lombardy, north Italy. Clinical characteristics and methodological aspects

Diabetes epidemiology can benefit in Italy from the large network of outpatient diabetic clinics and patients' facilities. A large investigation was carried out in 1988, in a certain area of northern Italy, to estimate the prevalence of known diabetes. Using four information sources, 4547 distinct patients were identified. Through the capture-recapture method we assessed completeness and estimated a prevalence of 3.3%. Prevalence of type 1 diabetes was 0.8 per 1000. Italian age-standardised overall prevalence and developed-world standardised rates were 2.8% and 2.6%, respectively. A representative sample of 2358 patients was characterised through a standard questionnaire. Women were diagnosed about 6 years later than men (58.8 +/- 0.4 vs 52.9 +/- 0.4, P < 0.0001), while the duration of the disease was very similar in both sexes (9.9 +/- 0.2 vs 9.5 +/- 0.2). As regards diabetes therapy, 17.2% of the patients were on diet alone, 62.1% on oral agents and 20.6% on insulin. Among the insulin-treated subjects more than half were on adjuvant therapy with tablets, and only 6.2% were treated with 3 injections/day. Less than half of all the known diabetic subjects had had an ophthalmoscopic examination in the previous 2 years.

Incidence of IDDM during 1988-1992 in Zagreb, Croatia

The objective of this study was to determine the incidence of insulin-dependent diabetes mellitus (IDDM) in the population of Zagreb, Croatia, during 1988-1992. A centralized diabetes registry was the primary source of data, while secondary sources were used to assess ascertainment. A total of 282 new cases of IDDM were diagnosed in the study period, the primary and secondary sources identifying annually 93-100% of the cases. The annual incidence rate ranged from 5.6 per 100,000 to 6.6 per 100,000. Early fatality in persons older than 50 years was the major cause of underascertainment. The incidence peaked in the 10-14 years age group (12.4 per 100,000), and remained stable after age 24 years. Males had a significantly higher incidence in the 5-9 and 24-44 years age groups. In the 45-54 years age group, females had a significantly higher incidence. No seasonality was observed. Despite the war conditions in Croatia, the low overall IDDM incidence rates did not change significantly during the study period.

A population-based prevalence survey of known diabetes mellitus in northern Italy based upon multiple independent sources of ascertainment

The aims of this survey were (1) to estimate the prevalence of known diabetes mellitus in 1988 in Casale Monferrato (Northern Italy); (2) to validate different data sources available in Italy; (3) to identify a population-based cohort of diabetic patients. Multiple independent data sources were used and the capture-recapture method was applied to estimate the completeness of ascertainment of the survey. The primary data source was the list of all patients attending the diabetic clinic or those referred by family physicians and paediatricians of the area. The secondary data sources were the list of hospital discharges, the prescriptions data source and the list of all people using reagent strips and insulin syringes. On 1 October 1988 (the cut-off date) 2,069 cases of known diabetes were identified. The estimated completeness of ascertainment of the survey was 91%. Prevalence of known diabetes, Type 1 (insulin-dependent), Type 2 (non-insulin-dependent) and insulin-treated diabetes were, respectively, 2.21% (95% CI 2.13-2.29), 0.80/1,000 (0.62-0.98) and 2.10% (2.01-2.19), 2.92/1,000 (2.57-3.27). A higher prevalence of Type 2 diabetes was observed in women (2.30%, 2.18-2.42) than in men (1.88%, 1.76-2.00). Age-specific prevalence of Type 2 diabetes increased with age. Computerized data sources routinely available in the Piedmont Region (hospital discharges and prescriptions data sources) showed a low completeness of ascertainment when considered together (65%, 1,338 of 2,069), indicating the need to involve the diabetic clinic and family physicians in the ascertainment of known diabetes. In conclusion, the prevalence of known diabetes in Italy was lower than in Northern Europe and the United States.